You could always just buy some new calipers from a local auto parts store, and get some blue caliper paint. An even better idea would be to get them power coated. It's far more expensive than paint, but it will last a lot longer. The paint tends to flake off after a while, and ends up looking worse than dirty stock parts.
But I've never seen a place online where you could buy them pre-painted or pre-powder coated.